Nuclear fears minimized in California

This satellite image provided by DigitalGlobe shows the damaged Fukushima Dai-ichi nuclear facility in Japan on Monday, March 14, 2011. Authorities are strugging to prevent the catastrophic release of radiation in the area devastated by a tsunami. (AP Photo/DigitalGlobe) MANDATORY CREDIT, EDITORIAL

/ AP

This satellite image provided by DigitalGlobe shows the damaged Fukushima Dai-ichi nuclear facility in Japan on Monday, March 14, 2011. Authorities are strugging to prevent the catastrophic release of radiation in the area devastated by a tsunami. (AP Photo/DigitalGlobe) MANDATORY CREDIT, EDITORIAL USE ONLY, NO SALES

This satellite image provided by DigitalGlobe shows the damaged Fukushima Dai-ichi nuclear facility in Japan on Monday, March 14, 2011. Authorities are strugging to prevent the catastrophic release of radiation in the area devastated by a tsunami. (AP Photo/DigitalGlobe) MANDATORY CREDIT, EDITORIAL USE ONLY, NO SALES (/ AP)

With unstable nuclear reactors in Japan threatening to create another wave of fallout from last week’s earthquake and tsunami, some Californians on Monday feared health threats that could emerge some 5,500 miles southeast of the disaster zone.

Several pollution experts said they are confident that local problems will be slim even if there’s a full nuclear meltdown. The biggest reason is the distance between here and there, but nuclear experts also cited confidence in Japanese disaster response efforts and engineering precautions at the sites to contain radiation.

Health leaders in Sacramento said they regularly test air, food and water for radiation and haven’t seen any elevated readings since Japan’s power plants started reeling on Friday.

“We really don’t feel it’s a danger to California,” said Michael Sicilia, a spokesman for the California Department of Public Health.

He said state residents don’t need to take any precautionary measures, and particularly should avoid taking iodine, which can be prescribed to combat radiation releases. Sicilia said it’s more important for people to be prepared in case natural disaster strikes closer to home.

Nuclear Regulatory Commission Chairman Gregory Jaczko said Monday at the White House that the type and design of the Japanese reactors and the way events have unfolded give him confidence that harmful levels of radiation will not reach the United States.

The U.S. Environmental Protection Agency has a radiation monitor at Kearny Mesa that is part of a national network known as RadNet. It was set up in the late 1950s to track fallout in the nuclear age, and more recently it has been used to monitor for radiation after fires at nuclear sites.

Murray Jennex, a business professor at SDSU with a history in the nuclear industry, echoed Jaczko’s sense of optimism.

“I have tested several containment structures like the ones in Japan, which is why I am confident they won’t have a major leak,” he said.

Still, many people who remember the Chernobyl disaster 25 years ago in Ukraine are leery about the reach of radiation. That accident — a meltdown and an explosion — showered Europe in radiation and shot particles around the globe. Also, the situation in Japan changes by the hour, and there’s no certainty how soon it will end.

Local concerns are boosted by research by the Scripps Institution of Oceanography in La Jolla that has shown more than three-quarters of the high-altitude soot particles that waft over the West Coast each spring are from Asia because of how the air currents typically move. It takes about five days for particles to transit the Pacific Ocean.

Q: Are the nuclear problems in Japan different from the disaster at Chernobyl?

A: Nuclear experts around the world on Monday said Japan’s reactors are better designed to limit radiation release and some doubted a full meltdown was possible at the Japan reactors. So far, their casings appear to be working. Also, Japan has moved quickly to evacuate residents instead of trying to cover up the problem as the Soviets did.

Q: What are the main pathways that radiation creates human health problems?

A: State and federal officials regularly sample air, water, foods and rain to check for radioactivity.

Q: What are main sources of radiation?

A: Nuclear power plants are on everyone’s mind now, but there are numerous natural sources. About half the radiation that people in the United States are exposed to annually comes from cosmic rays, radon emanating from the ground and other natural sources. The other half is linked to medical diagnostic tools such at CT scans. Amounts of radiation vary greatly by location; the U.S. Capitol is made mostly of granite and contains higher levels of radiation than most homes.

Q: How much radiation is too much?

A: There’s no set standard for what is safe but typical natural levels aren’t deemed harmful. Most people receive about 300 millirems of radiation each year from natural sources. Federal scientists said that 50 percent of a population would die within 30 days after receiving a dose of between 350,000 to 500,000 millirems to the whole body in a few hours or less.

Q: What steps can people take to protect themselves from radiation?

A: Japanese officials have issued at least 230,000 iodine tablets to people living near hobbled reactors in recent days. Raising the concentration of stable iodine in the blood increases the likelihood that the thyroid will absorb it instead of the radioactive kind. But that strategy brings risks — some people are allergic to iodine — and health officials said it should only be taken in an emergency.

Sources: U.S. Nuclear Regulatory Commission; U.S. Environmental Protection Agency; California Department of Public Health; San Diego State University.